JP2016144804A - Electrode for photolytic water decomposition reaction using photocatalyst - Google Patents
Electrode for photolytic water decomposition reaction using photocatalyst Download PDFInfo
- Publication number
- JP2016144804A JP2016144804A JP2016035141A JP2016035141A JP2016144804A JP 2016144804 A JP2016144804 A JP 2016144804A JP 2016035141 A JP2016035141 A JP 2016035141A JP 2016035141 A JP2016035141 A JP 2016035141A JP 2016144804 A JP2016144804 A JP 2016144804A
- Authority
- JP
- Japan
- Prior art keywords
- photocatalyst
- electrode
- semiconductor
- support
- good conductor
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 239000011941 photocatalyst Substances 0.000 title claims abstract description 142
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 title abstract description 38
- 238000000354 decomposition reaction Methods 0.000 title abstract description 8
- 239000002245 particle Substances 0.000 claims abstract description 91
- 239000004020 conductor Substances 0.000 claims abstract description 62
- 239000004065 semiconductor Substances 0.000 claims abstract description 55
- 239000002243 precursor Substances 0.000 claims abstract description 18
- 238000000576 coating method Methods 0.000 claims abstract description 11
- XTQHKBHJIVJGKJ-UHFFFAOYSA-N sulfur monoxide Chemical compound S=O XTQHKBHJIVJGKJ-UHFFFAOYSA-N 0.000 claims abstract description 11
- UCKMPCXJQFINFW-UHFFFAOYSA-N Sulphide Chemical compound [S-2] UCKMPCXJQFINFW-UHFFFAOYSA-N 0.000 claims abstract description 9
- 150000004767 nitrides Chemical class 0.000 claims abstract description 9
- 239000011248 coating agent Substances 0.000 claims abstract description 7
- 238000006243 chemical reaction Methods 0.000 claims description 46
- 229910052718 tin Inorganic materials 0.000 claims description 38
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical group [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 claims description 31
- 238000000034 method Methods 0.000 claims description 23
- 238000011282 treatment Methods 0.000 claims description 23
- 229910052719 titanium Inorganic materials 0.000 claims description 21
- -1 Ta 3 N 5 Inorganic materials 0.000 claims description 18
- 238000004519 manufacturing process Methods 0.000 claims description 17
- 229910052759 nickel Inorganic materials 0.000 claims description 12
- 229910052787 antimony Inorganic materials 0.000 claims description 11
- 229910052804 chromium Inorganic materials 0.000 claims description 10
- 229910052742 iron Inorganic materials 0.000 claims description 10
- 229910003071 TaON Inorganic materials 0.000 claims description 9
- 229910045601 alloy Inorganic materials 0.000 claims description 9
- 239000000956 alloy Substances 0.000 claims description 9
- 229910052799 carbon Inorganic materials 0.000 claims description 9
- 229910052802 copper Inorganic materials 0.000 claims description 9
- 229910006404 SnO 2 Inorganic materials 0.000 claims description 8
- 229910010413 TiO 2 Inorganic materials 0.000 claims description 8
- 229910052793 cadmium Inorganic materials 0.000 claims description 8
- 229910052733 gallium Inorganic materials 0.000 claims description 8
- 238000010438 heat treatment Methods 0.000 claims description 8
- 229910052738 indium Inorganic materials 0.000 claims description 8
- 229910052745 lead Inorganic materials 0.000 claims description 8
- 239000000203 mixture Substances 0.000 claims description 8
- 229910052750 molybdenum Inorganic materials 0.000 claims description 8
- 229910052758 niobium Inorganic materials 0.000 claims description 8
- 229910052703 rhodium Inorganic materials 0.000 claims description 8
- 229910052707 ruthenium Inorganic materials 0.000 claims description 8
- XLOMVQKBTHCTTD-UHFFFAOYSA-N zinc oxide Inorganic materials [Zn]=O XLOMVQKBTHCTTD-UHFFFAOYSA-N 0.000 claims description 8
- 229910052741 iridium Inorganic materials 0.000 claims description 7
- 229910052748 manganese Inorganic materials 0.000 claims description 7
- 229910052702 rhenium Inorganic materials 0.000 claims description 7
- 229910052715 tantalum Inorganic materials 0.000 claims description 7
- 229910052720 vanadium Inorganic materials 0.000 claims description 7
- 229910052737 gold Inorganic materials 0.000 claims description 6
- 229910052709 silver Inorganic materials 0.000 claims description 6
- 238000005979 thermal decomposition reaction Methods 0.000 claims description 3
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 abstract description 14
- 229910052739 hydrogen Inorganic materials 0.000 abstract description 14
- 239000001257 hydrogen Substances 0.000 abstract description 14
- 239000000463 material Substances 0.000 abstract description 10
- 239000010936 titanium Substances 0.000 description 51
- 229910052751 metal Inorganic materials 0.000 description 24
- 239000002184 metal Substances 0.000 description 24
- 239000000243 solution Substances 0.000 description 23
- 238000007654 immersion Methods 0.000 description 14
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 12
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 10
- 230000001699 photocatalysis Effects 0.000 description 10
- PXHVJJICTQNCMI-UHFFFAOYSA-N nickel Substances [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 9
- 239000011701 zinc Substances 0.000 description 9
- 229910001069 Ti alloy Inorganic materials 0.000 description 7
- 238000000151 deposition Methods 0.000 description 7
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 7
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 6
- 238000001035 drying Methods 0.000 description 6
- 238000005121 nitriding Methods 0.000 description 6
- 239000001301 oxygen Substances 0.000 description 6
- 229910052760 oxygen Inorganic materials 0.000 description 6
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 6
- 238000001878 scanning electron micrograph Methods 0.000 description 6
- 229910052757 nitrogen Inorganic materials 0.000 description 5
- 230000002441 reversible effect Effects 0.000 description 5
- 238000004544 sputter deposition Methods 0.000 description 5
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 description 4
- 229910002367 SrTiO Inorganic materials 0.000 description 4
- 239000007864 aqueous solution Substances 0.000 description 4
- 239000003054 catalyst Substances 0.000 description 4
- 239000008151 electrolyte solution Substances 0.000 description 4
- 239000007789 gas Substances 0.000 description 4
- 229910052697 platinum Inorganic materials 0.000 description 4
- 230000002829 reductive effect Effects 0.000 description 4
- LYCAIKOWRPUZTN-UHFFFAOYSA-N Ethylene glycol Chemical compound OCCO LYCAIKOWRPUZTN-UHFFFAOYSA-N 0.000 description 3
- 229910021607 Silver chloride Inorganic materials 0.000 description 3
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 3
- KRKNYBCHXYNGOX-UHFFFAOYSA-N citric acid Chemical compound OC(=O)CC(O)(C(O)=O)CC(O)=O KRKNYBCHXYNGOX-UHFFFAOYSA-N 0.000 description 3
- 230000008021 deposition Effects 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- HTXDPTMKBJXEOW-UHFFFAOYSA-N dioxoiridium Chemical compound O=[Ir]=O HTXDPTMKBJXEOW-UHFFFAOYSA-N 0.000 description 3
- 238000004070 electrodeposition Methods 0.000 description 3
- 238000005516 engineering process Methods 0.000 description 3
- 229910000457 iridium oxide Inorganic materials 0.000 description 3
- 238000004080 punching Methods 0.000 description 3
- HKZLPVFGJNLROG-UHFFFAOYSA-M silver monochloride Chemical compound [Cl-].[Ag+] HKZLPVFGJNLROG-UHFFFAOYSA-M 0.000 description 3
- OGIDPMRJRNCKJF-UHFFFAOYSA-N titanium oxide Inorganic materials [Ti]=O OGIDPMRJRNCKJF-UHFFFAOYSA-N 0.000 description 3
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 description 2
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
- MYMOFIZGZYHOMD-UHFFFAOYSA-N Dioxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 description 2
- 229910052782 aluminium Inorganic materials 0.000 description 2
- 238000005229 chemical vapour deposition Methods 0.000 description 2
- 229910001882 dioxygen Inorganic materials 0.000 description 2
- 239000010408 film Substances 0.000 description 2
- 239000003014 ion exchange membrane Substances 0.000 description 2
- 229910052746 lanthanum Inorganic materials 0.000 description 2
- 239000012528 membrane Substances 0.000 description 2
- QGLKJKCYBOYXKC-UHFFFAOYSA-N nonaoxidotritungsten Chemical compound O=[W]1(=O)O[W](=O)(=O)O[W](=O)(=O)O1 QGLKJKCYBOYXKC-UHFFFAOYSA-N 0.000 description 2
- 230000003287 optical effect Effects 0.000 description 2
- 229910052763 palladium Inorganic materials 0.000 description 2
- KDLHZDBZIXYQEI-UHFFFAOYSA-N palladium Substances [Pd] KDLHZDBZIXYQEI-UHFFFAOYSA-N 0.000 description 2
- 238000005240 physical vapour deposition Methods 0.000 description 2
- 239000000843 powder Substances 0.000 description 2
- 230000006798 recombination Effects 0.000 description 2
- 238000005215 recombination Methods 0.000 description 2
- 238000003980 solgel method Methods 0.000 description 2
- 239000000725 suspension Substances 0.000 description 2
- 229910001930 tungsten oxide Inorganic materials 0.000 description 2
- 238000001771 vacuum deposition Methods 0.000 description 2
- ZCYVEMRRCGMTRW-UHFFFAOYSA-N 7553-56-2 Chemical compound [I] ZCYVEMRRCGMTRW-UHFFFAOYSA-N 0.000 description 1
- 229910000838 Al alloy Inorganic materials 0.000 description 1
- 229910000975 Carbon steel Inorganic materials 0.000 description 1
- 229910020599 Co 3 O 4 Inorganic materials 0.000 description 1
- 229910002422 La(NO3)3·6H2O Inorganic materials 0.000 description 1
- 229910000909 Lead-bismuth eutectic Inorganic materials 0.000 description 1
- 229910019899 RuO Inorganic materials 0.000 description 1
- 229910052776 Thorium Inorganic materials 0.000 description 1
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 1
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 description 1
- QCWXUUIWCKQGHC-UHFFFAOYSA-N Zirconium Chemical compound [Zr] QCWXUUIWCKQGHC-UHFFFAOYSA-N 0.000 description 1
- 239000003929 acidic solution Substances 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 229910021529 ammonia Inorganic materials 0.000 description 1
- WATWJIUSRGPENY-UHFFFAOYSA-N antimony atom Chemical compound [Sb] WATWJIUSRGPENY-UHFFFAOYSA-N 0.000 description 1
- 239000003637 basic solution Substances 0.000 description 1
- 229910052980 cadmium sulfide Inorganic materials 0.000 description 1
- 239000010962 carbon steel Substances 0.000 description 1
- 238000003763 carbonization Methods 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- IVMYJDGYRUAWML-UHFFFAOYSA-N cobalt(II) oxide Inorganic materials [Co]=O IVMYJDGYRUAWML-UHFFFAOYSA-N 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 239000002772 conduction electron Substances 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000007598 dipping method Methods 0.000 description 1
- 239000003792 electrolyte Substances 0.000 description 1
- 238000001962 electrophoresis Methods 0.000 description 1
- 230000001747 exhibiting effect Effects 0.000 description 1
- 238000010304 firing Methods 0.000 description 1
- 239000000446 fuel Substances 0.000 description 1
- 229910002804 graphite Inorganic materials 0.000 description 1
- 239000010439 graphite Substances 0.000 description 1
- 238000006460 hydrolysis reaction Methods 0.000 description 1
- 230000001939 inductive effect Effects 0.000 description 1
- 230000002401 inhibitory effect Effects 0.000 description 1
- 229910052740 iodine Inorganic materials 0.000 description 1
- 239000011630 iodine Substances 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 125000001449 isopropyl group Chemical group [H]C([H])([H])C([H])(*)C([H])([H])[H] 0.000 description 1
- 239000007791 liquid phase Substances 0.000 description 1
- 230000007935 neutral effect Effects 0.000 description 1
- GNRSAWUEBMWBQH-UHFFFAOYSA-N nickel(II) oxide Inorganic materials [Ni]=O GNRSAWUEBMWBQH-UHFFFAOYSA-N 0.000 description 1
- 229910052755 nonmetal Inorganic materials 0.000 description 1
- 230000000149 penetrating effect Effects 0.000 description 1
- 238000005504 petroleum refining Methods 0.000 description 1
- 238000013032 photocatalytic reaction Methods 0.000 description 1
- 238000005498 polishing Methods 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 239000000376 reactant Substances 0.000 description 1
- 230000027756 respiratory electron transport chain Effects 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 238000007650 screen-printing Methods 0.000 description 1
- 150000003346 selenoethers Chemical class 0.000 description 1
- 238000004528 spin coating Methods 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 239000007858 starting material Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 239000000758 substrate Substances 0.000 description 1
- 150000004763 sulfides Chemical class 0.000 description 1
- 230000002194 synthesizing effect Effects 0.000 description 1
- 239000010409 thin film Substances 0.000 description 1
- XOLBLPGZBRYERU-UHFFFAOYSA-N tin dioxide Chemical compound O=[Sn]=O XOLBLPGZBRYERU-UHFFFAOYSA-N 0.000 description 1
- 229910001887 tin oxide Inorganic materials 0.000 description 1
- 229910052721 tungsten Inorganic materials 0.000 description 1
- 238000001947 vapour-phase growth Methods 0.000 description 1
- 238000010792 warming Methods 0.000 description 1
- 229910052725 zinc Inorganic materials 0.000 description 1
- 229910052726 zirconium Inorganic materials 0.000 description 1
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/30—Hydrogen technology
- Y02E60/36—Hydrogen production from non-carbon containing sources, e.g. by water electrolysis
Landscapes
- Catalysts (AREA)
- Electrodes For Compound Or Non-Metal Manufacture (AREA)
- Electrolytic Production Of Non-Metals, Compounds, Apparatuses Therefor (AREA)
Abstract
Description
本発明は、太陽光を利用した水分解反応を行うことにより水素を製造する装置に適用される、支持体上に光触媒を備えてなる光水分解反応用電極に関する。 The present invention relates to an electrode for photo-water splitting reaction, which is applied to an apparatus for producing hydrogen by performing water-splitting reaction using sunlight, and includes a photocatalyst on a support.
太陽エネルギーなどの再生可能エネルギーを利用した高性能な光エネルギー変換システムを実用化することは、地球温暖化の抑制、および枯渇しつつある化石資源依存からの脱却を目指す観点から、近年になって急激にその重要性が増している。中でも、太陽エネルギーを用いて水を分解し水素を製造する技術は、現行の石油精製、アンモニア、メタノールの原料供給技術としてのみならず、燃料電池をベースとした来たる水素エネルギー社会において、必須とされる技術である。 In recent years, the practical application of high-performance light energy conversion systems that use renewable energy such as solar energy has been aimed at controlling global warming and moving away from the depletion of fossil resources. Its importance is increasing rapidly. Above all, the technology that decomposes water using solar energy to produce hydrogen is indispensable not only in the current petroleum refining, ammonia and methanol raw material supply technology, but also in the future hydrogen energy society based on fuel cells. Technology.
光触媒による水分解反応は、１９７０年代から広く研究されている（非特許文献１）。光触媒の多くはその大きなバンドギャップのため、紫外光領域でならば水分解が進行するが可視光領域は利用できなかったり、可視光領域を利用することができても水中で不安定であったりするという欠点があった。２０００年以降になって可視光領域の光エネルギーで水を分解することができ、かつ水中で安定である光触媒が発表されるようになった（非特許文献２、３、４）。これらは粉体状の光触媒をそのまま使用するか、もしくはキャラクタリゼーションのしやすいＮｂ：ＳｒＴｉＯ３ やＦ：ＳｎＯ２などの酸化物導電体上に光触媒を堆積して反応に使用するのが一般的であった。 The water splitting reaction using a photocatalyst has been extensively studied since the 1970s (Non-Patent Document 1). Many photocatalysts have a large band gap, so water decomposition proceeds in the ultraviolet region, but the visible region cannot be used, or even if the visible region can be used, it is unstable in water. There was a drawback of doing. Since 2000, photocatalysts that can decompose water with light energy in the visible light region and are stable in water have been announced (Non-Patent Documents 2, 3, and 4). These are generally used in the reaction by using a powdery photocatalyst as it is or by depositing a photocatalyst on an oxide conductor such as Nb: SrTiO 3 or F: SnO 2 which is easy to characterize. there were.
粉体状の光触媒を用いて懸濁液の中で水分解反応を行う場合、よりエネルギー的に有利な逆反応が進行してしまうために光電変換効率が低い上、水分解反応による水素生成サイトと酸素生成サイトは懸濁された光触媒粒子上にあって不可分なため、生成ガスは混合気体として回収せざるを得ないという欠点があった。 When a water splitting reaction is carried out in a suspension using a powder photocatalyst, a more energy-friendly reverse reaction proceeds, so the photoelectric conversion efficiency is low and the hydrogen generation site by the water splitting reaction Since the oxygen generation site is inseparable on the suspended photocatalyst particles, the product gas must be recovered as a mixed gas.
また、酸化物導電体上に光触媒を堆積し、対極として適当な触媒を使用すれば、水素生成サイトと酸素生成サイトを分離して逆反応を抑制すると共に水素ガスと酸素ガスを分離した状態で回収することができる。しかしながら酸化物導電体はコストが高くなるうえ、酸化物導電体と光触媒のエネルギー準位のマッチングが難しいという問題があった。 In addition, if a photocatalyst is deposited on the oxide conductor and an appropriate catalyst is used as the counter electrode, the hydrogen generation site and the oxygen generation site are separated to suppress the reverse reaction and the hydrogen gas and the oxygen gas are separated. It can be recovered. However, the oxide conductor has a problem that the cost is high and it is difficult to match the energy levels of the oxide conductor and the photocatalyst.
一方、金属電極（金属支持体）は、酸化物導電体電極に比べ、加工性、形状制御性およびコスト面において優れている。さらに、金属は高い導電性（伝導電子密度）を持つことから光触媒との導通をとりやすく、金属支持体上に堆積した光触媒に適当な電圧をかけることにより、光触媒反応を促進することができる。パンチングメタルや多数の貫通細孔を持つ金属基板に光触媒および白金を堆積し、これらを対にしてプロトン伝導膜を介して水分解を行う方法が提案されている（特許文献１）。 On the other hand, a metal electrode (metal support) is superior in terms of workability, shape controllability, and cost compared to an oxide conductor electrode. Furthermore, since the metal has high conductivity (conducting electron density), it is easy to conduct with the photocatalyst, and the photocatalytic reaction can be promoted by applying an appropriate voltage to the photocatalyst deposited on the metal support. There has been proposed a method in which a photocatalyst and platinum are deposited on a punching metal or a metal substrate having a large number of through-holes, and water is decomposed through a proton conducting membrane by pairing them (Patent Document 1).
金属支持体上への光触媒の堆積方法としては、真空蒸着法やスパッタリング法に代表される物理気相成長（ＰＶＤ）法や化学気相成長（ＣＶＤ）法、スピンコーティングやスクリーン印刷に代表される塗布法やゾル−ゲル法、電気泳動法に代表される液相成長法が知られており、中でも電気泳動電着（ＥＰＤ）によるコーティング法（非特許文献５、特許文献２） は大面積で複雑な形状を持つ電極に対し、安価でコーティング膜厚制御が容易な手法として注目されている。 As a method for depositing a photocatalyst on a metal support, a physical vapor deposition (PVD) method or a chemical vapor deposition (CVD) method represented by a vacuum deposition method or a sputtering method, a spin coating or a screen printing is represented. Liquid phase growth methods represented by coating methods, sol-gel methods, and electrophoresis methods are known. Among them, coating methods by electrophoretic electrodeposition (EPD) (Non-Patent Documents 5 and 2) have a large area. Attention has been focused on an electrode having a complicated shape as an inexpensive and easy-to-control coating film thickness method.
しかしながら、塗布法や電気泳動電着法など、溶液中に懸濁させた光触媒粒子を出発原料として金属支持体に堆積する場合、もともとの光触媒粒子のサイズが大きいため、金属支持体表面に密に堆積するのが難しいという欠点があった。また支持体表面−光触媒粒子間、および光触媒粒子同士の接触面が小さいために抵抗が生じ、光触媒膜内部の電子伝導性、および光触媒−支持体表面間の電子伝導性が著しく低下してしまうという問題があった。 However, when photocatalyst particles suspended in a solution are deposited on a metal support as a starting material, such as a coating method or an electrophoretic electrodeposition method, the original photocatalyst particles are large in size, so that the surface of the metal support is closely packed. There was the disadvantage that it was difficult to deposit. In addition, resistance occurs because the contact surface between the support surface and the photocatalyst particles and between the photocatalyst particles is small, and the electron conductivity inside the photocatalyst film and the electron conductivity between the photocatalyst and the support surface are significantly reduced. There was a problem.
光触媒粒子間、および光触媒−支持体間の電子伝導性を向上させるために、使用する光触媒よりも高い伝導性を持つ半導体もしくは良導体で光触媒粒子の周囲を覆う手法が提案されている。例えば、光触媒である酸化鉄もしくは酸化タングステン粒子の周囲をチタン、アルミニウム、アンチモン、スズ、亜鉛、ジルコニウム等の酸化物半導体で覆い、導電性を向上させる方法が提案されている（特許文献３）。 In order to improve the electron conductivity between the photocatalyst particles and between the photocatalyst and the support, a method of covering the periphery of the photocatalyst particles with a semiconductor or a good conductor having higher conductivity than the photocatalyst to be used has been proposed. For example, a method has been proposed in which the periphery of iron oxide or tungsten oxide particles as a photocatalyst is covered with an oxide semiconductor such as titanium, aluminum, antimony, tin, zinc, or zirconium to improve conductivity (Patent Document 3).
しかしながら、光触媒である酸化鉄や酸化タングステンに対し、酸化チタンなどの光触媒と異なる金属種の酸化物を導電体として用いた場合、それぞれのエネルギーレベルが大きく異なるためにレベルのミスマッチが生じ、これが抵抗となって導電性が低下してしまう問題があった。 However, when iron oxide or tungsten oxide, which is a photocatalyst, is used as a conductor, an oxide of a metal species different from the photocatalyst such as titanium oxide, the level of energy differs greatly, resulting in a level mismatch, which is a resistance. As a result, there is a problem that the conductivity is lowered.
本発明は、光水分解反応用の電極であって、光触媒粒子を支持体上に堆積させ、光触媒粒子間および光触媒−支持体間に、抵抗を減ずるための半導体または良導体を有するものとして、光触媒層の電子伝導性を良好にし、光電変換効率を向上させることにより、光照射下における光水分解反応速度を飛躍的に増大させることができる、効率的で工業的に有利な水素製造用の光水分解反応用電極を提供することを目的とする。 The present invention relates to a photocatalyst as an electrode for photohydrolysis reaction, having photocatalyst particles deposited on a support and having a semiconductor or a good conductor for reducing resistance between the photocatalyst particles and between the photocatalyst and the support. Efficient and industrially advantageous light for hydrogen production, which can dramatically increase the photo-hydrolysis reaction rate under light irradiation by improving the electron conductivity of the layer and improving the photoelectric conversion efficiency An object is to provide an electrode for water splitting reaction.
本発明者らは、上記の課題を解決すべく鋭意検討し、以下の事項を見出すに至った。
（１）光触媒成分であるオキシナイトライド、ナイトライド、オキシサルファイド、サルファイドを合成し、この粒子を支持体上に堆積した後に、光触媒の粒子間抵抗および光触媒−支持体間の抵抗を低減する処理を実施する。
（２）光触媒の粒子間抵抗および光触媒−支持体間の抵抗を低減する処理として、光触媒粒子の周囲に半導体もしくは良導体を付与する。
（３）該半導体もしくは良導体としては、用いる光触媒とエネルギーレベルが近いか、もしくは金属のように十分な伝導電子密度を持ち、かつ水分解反応の逆反応や、光触媒電極が触媒する水分解反応の対極で進行する反応を触媒しないものとする。また、簡便な操作で光触媒粒子の周囲に付与できるものとする。
The present inventors diligently studied to solve the above problems, and have found the following matters.
(1) Treatment for reducing photocatalyst interparticle resistance and photocatalyst-support resistance after synthesizing oxynitride, nitride, oxysulfide, and sulfide as photocatalyst components and depositing the particles on the support. To implement.
(2) As a treatment for reducing the resistance between the particles of the photocatalyst and the resistance between the photocatalyst and the support, a semiconductor or a good conductor is provided around the photocatalyst particles.
(3) The semiconductor or good conductor has an energy level close to that of the photocatalyst used, or has a sufficient conduction electron density like a metal, and is a reverse reaction of the water splitting reaction or a water splitting reaction catalyzed by the photocatalytic electrode. The reaction that proceeds at the counter electrode shall not be catalyzed. Further, it can be applied around the photocatalyst particles by a simple operation.
以上の検討事項を元に、本発明者らは以下の発明を完成させた。なお、本発明の理解を容易にするために添付図面の参照符号を括弧書きにて付記するが、これにより本発明が図示の形態に限定されるものではない。
第１の本発明は、光触媒粒子を構成する光触媒として、オキシナイトライド、ナイトライド、オキシサルファイド、および、サルファイドからなる群から選ばれる１種以上が支持体上に堆積されてなるとともに、前記光触媒粒子の周囲に半導体または良導体が付与された光水分解反応用電極の製造方法であって、前記半導体または良導体が、ＴｉＮ、ＴｉＯ２、Ｔａ３Ｎ５、ＴａＯＮ、ＺｎＯ、ＳｎＯ２、ＩＴＯ、Ａｇ、Ａｕ、Ｃ、Ｃｕ、Ｃｄ、Ｃｏ、Ｃｒ、Ｆｅ、Ｇａ、Ｇｅ、Ｈｇ、Ｉｒ、Ｉｎ、Ｍｎ、Ｍｏ、Ｎｉ、Ｎｂ、Ｐｂ、Ｒｕ、Ｒｅ、Ｒｈ、Ｓｎ、Ｓｂ、Ｔａ、Ｔｉ、Ｖ、Ｗ、並びに、これらの合金および混合物から選ばれるいずれかであり、前記半導体または良導体の前駆体溶液に前記光触媒粒子を浸漬して、該半導体または良導体の前駆体で該光触媒粒子をコーティングした後、熱分解処理を行うことを特徴とする、光水分解反応用電極の製造方法である。
第２の本発明は、光触媒粒子を構成する光触媒として、オキシナイトライド、ナイトライド、オキシサルファイド、および、サルファイドからなる群から選ばれる１種以上が支持体上に堆積されてなる電極であって、前記光触媒粒子間ならびに前記光触媒粒子および前記支持体間に半導体または良導体を有し、且つ、前記半導体または良導体が、ＴｉＮ、ＴｉＯ２、Ｔａ３Ｎ５、ＴａＯＮ、ＺｎＯ、ＳｎＯ２、ＩＴＯ、Ａｇ、Ａｕ、Ｃ、Ｃｕ、Ｃｄ、Ｃｏ、Ｃｒ、Ｆｅ、Ｇａ、Ｇｅ、Ｈｇ、Ｉｒ、Ｉｎ、Ｍｎ、Ｍｏ、Ｎｉ、Ｎｂ、Ｐｂ、Ｒｕ、Ｒｅ、Ｒｈ、Ｓｎ、Ｓｂ、Ｔａ、Ｔｉ、Ｖ、Ｗ、並びに、これらの合金および混合物から選ばれるいずれかであり、前記半導体または良導体の前駆体で前記光触媒粒子および前記支持体表面をコーティングした後に熱処理を行うことにより、前記光触媒粒子間ならびに前記光触媒粒子および前記支持体間に半導体または良導体が付与されていることを特徴とする、光水分解反応用電極である。
第３の本発明は、光触媒粒子を構成する光触媒として、オキシナイトライド、ナイトライド、オキシサルファイド、および、サルファイドからなる群から選ばれる１種以上が支持体上に堆積されてなる光水分解反応用電極の製造方法であって、前記光触媒粒子間ならびに前記光触媒粒子および前記支持体間に半導体または良導体を有し、且つ、前記半導体または良導体が、ＴｉＮ、ＴｉＯ２、Ｔａ３Ｎ５、ＴａＯＮ、ＺｎＯ、ＳｎＯ２、ＩＴＯ、Ａｇ、Ａｕ、Ｃ、Ｃｕ、Ｃｄ、Ｃｏ、Ｃｒ、Ｆｅ、Ｇａ、Ｇｅ、Ｈｇ、Ｉｒ、Ｉｎ、Ｍｎ、Ｍｏ、Ｎｉ、Ｎｂ、Ｐｂ、Ｒｕ、Ｒｅ、Ｒｈ、Ｓｎ、Ｓｂ、Ｔａ、Ｔｉ、Ｖ、Ｗ、並びに、これらの合金および混合物から選ばれるいずれかであり、前記半導体または良導体の前駆体で前記光触媒粒子および前記支持体表面をコーティングした後に熱処理を行うことにより、前記光触媒粒子間ならびに前記光触媒粒子および前記支持体間に前記半導体または前記良導体を付与することを特徴とする、光水分解反応用電極の製造方法である。
Based on the above considerations, the present inventors have completed the following invention. In order to facilitate understanding of the present invention, reference numerals in the accompanying drawings are added in parentheses, but the present invention is not limited to the illustrated embodiment.
According to the first aspect of the present invention, at least one selected from the group consisting of oxynitride, nitride, oxysulfide, and sulfide is deposited on a support as a photocatalyst constituting the photocatalyst particles, and the photocatalyst A method for producing an electrode for photohydrolysis reaction in which a semiconductor or a good conductor is provided around particles, wherein the semiconductor or the good conductor is TiN, TiO 2 , Ta 3 N 5 , TaON, ZnO, SnO 2 , ITO, Ag , Au, C, Cu, Cd, Co, Cr, Fe, Ga, Ge, Hg, Ir, In, Mn, Mo, Ni, Nb, Pb, Ru, Re, Rh, Sn, Sb, Ta, Ti, V , W, and alloys and mixtures thereof, the photocatalyst particles are immersed in the semiconductor or good conductor precursor solution, After coating the photocatalyst particles in the precursor conductor, and performing thermal decomposition process, a method for manufacturing an optical water decomposition reaction electrode.
The second aspect of the present invention is an electrode in which at least one selected from the group consisting of oxynitride, nitride, oxysulfide, and sulfide is deposited on a support as a photocatalyst constituting photocatalyst particles. And between the photocatalyst particles and between the photocatalyst particles and the support, and the semiconductor or good conductor is TiN, TiO 2 , Ta 3 N 5 , TaON, ZnO, SnO 2 , ITO, Ag , Au, C, Cu, Cd, Co, Cr, Fe, Ga, Ge, Hg, Ir, In, Mn, Mo, Ni, Nb, Pb, Ru, Re, Rh, Sn, Sb, Ta, Ti, V , W, and alloys and mixtures thereof, and the photocatalyst particles and the support surface with the precursor of the semiconductor or good conductor. By performing the heat treatment after computing, wherein the semiconductor or conductor has been applied between the between the photocatalyst particles and the photocatalyst particles and the support, a light-water decomposition reaction electrode.
The third aspect of the present invention is a photohydrolysis reaction in which at least one selected from the group consisting of oxynitride, nitride, oxysulfide, and sulfide is deposited on a support as a photocatalyst constituting photocatalyst particles. A method for producing an electrode for a semiconductor, comprising a semiconductor or a good conductor between the photocatalyst particles and between the photocatalyst particles and the support, wherein the semiconductor or good conductor is TiN, TiO 2 , Ta 3 N 5 , TaON, ZnO, SnO 2, ITO, Ag , Au, C, Cu, Cd, Co, Cr, Fe, Ga, Ge, Hg, Ir, In, Mn, Mo, Ni, Nb, Pb, Ru, Re, Rh, Sn , Sb, Ta, Ti, V, W, and alloys and mixtures thereof, and the photocatalyst particles in the semiconductor or good conductor precursor And applying a heat treatment after coating the surface of the support to provide the semiconductor or the good conductor between the photocatalyst particles and between the photocatalyst particles and the support. It is a manufacturing method.
本発明において、光触媒粒子（１０）は、ＬａＴｉＯ２Ｎ、ＣａＮｂＯ２Ｎ、または、Ｇａ１−ｘＺｎｘＮ１−ｘＯｘ（ｘは、０〜１の数値を表す。）のいずれかの粒子、あるいは、これらの二種以上の混合物であることが好ましい。 In the present invention, the photocatalyst particles (10) are either LaTiO 2 N, CaNbO 2 N, or Ga 1-x Zn x N 1-x O x (x represents a numerical value of 0 to 1 ). Particles or a mixture of two or more of these are preferred.
本発明において、半導体または良導体（３０）は、支持体（２０）の金属と同一の元素を含むことが好ましい。 In the present invention, the semiconductor or good conductor (30) preferably contains the same element as the metal of the support (20).
本発明において、支持体（２０）は、チタン、チタン合金、または、チタン若しくはチタン合金を表面にコートした金属のいずれかであることが好ましい。 In the present invention, the support (20) is preferably titanium, a titanium alloy, or a metal whose surface is coated with titanium or a titanium alloy.
本発明において、半導体または良導体（３０）はチタンを含むことが好ましい。また、半導体または良導体（３０）はＴｉＮであることが好ましい。 In the present invention, the semiconductor or good conductor (30) preferably contains titanium. The semiconductor or good conductor (30) is preferably TiN.
本発明において、支持体（２０）の形状は、パンチングメタル状、メッシュ状、格子状、または、貫通した細孔を持つ多孔体のいずれかであることが好ましい。 In the present invention, the shape of the support (20) is preferably a punching metal shape, a mesh shape, a lattice shape, or a porous body having penetrating pores.
本発明によれば、支持体（２０）上に光触媒粒子（１０）を堆積した光水分解反応用電極において、光触媒粒子（１０）の周囲に半導体または良導体（３０）を有するものとすることによって電極の内部抵抗を低下させ、光電変換効率を向上させることができる。
本発明によれば、光照射によって光触媒内部に生じた電子と正孔のうち、電子を半導体または良導体（３０）へ誘導することによって再結合を抑制し、光電変換効率を向上させることができる。
According to the present invention, in the electrode for water splitting reaction in which the photocatalyst particles (10) are deposited on the support (20), the semiconductor or the good conductor (30) is provided around the photocatalyst particles (10). The internal resistance of the electrode can be reduced and the photoelectric conversion efficiency can be improved.
ADVANTAGE OF THE INVENTION According to this invention, recombination can be suppressed by inducing an electron to a semiconductor or a good conductor (30) among the electron and the hole which arose inside the photocatalyst by light irradiation, and a photoelectric conversion efficiency can be improved.
＜水分解反応装置（二電極系）＞
図９に、水分解反応装置（二電極系）の概念図を示す。図９においては、光触媒電極６１と対極６３とが導体６４により接続され、それぞれ電解質水溶液６５に浸漬されている。光触媒電極６１と対極６３の電解液は、隔膜またはイオン交換膜６２により隔てられている。図９では、アノードとして本発明の光触媒電極６１を用い、カソードとして対極６３を用いているが、カソードに本発明の光触媒電極を用いてもよいし、また、アノードおよびカソード共に、本発明の光触媒電極を用いてもよい。なお、カソードに本発明の光触媒電極を用いた場合は、太陽光はカソード側から取り入れるようにし、また、アノードおよびカソード共に、本発明の光触媒電極を用いた場合は、太陽光はアノードおよびカソード両方の側から取り入れる。
<Water splitting reactor (two electrode system)>
In FIG. 9, the conceptual diagram of a water splitting reaction apparatus (two electrode system) is shown. In FIG. 9, the photocatalytic electrode 61 and the counter electrode 63 are connected by a conductor 64 and are each immersed in an aqueous electrolyte solution 65. The electrolyte solution of the photocatalyst electrode 61 and the counter electrode 63 is separated by a diaphragm or an ion exchange membrane 62. In FIG. 9, the photocatalyst electrode 61 of the present invention is used as the anode and the counter electrode 63 is used as the cathode. However, the photocatalyst electrode of the present invention may be used as the cathode, and the photocatalyst of the present invention may be used for both the anode and the cathode. An electrode may be used. When the photocatalytic electrode of the present invention is used for the cathode, sunlight is taken from the cathode side, and when the photocatalytic electrode of the present invention is used for both the anode and the cathode, the sunlight is both for the anode and the cathode. Take in from the side.
一般的に、水素ガスと酸素ガスを別々に回収する水分解反応装置においては、光触媒電極と対極とで構成される二電極系を使用する。二電極系での水の分解反応において、酸性溶液中では、各々の電極上で以下の反応が進行している。
（アノード）Ｈ２Ｏ＋２ｈ＋→１／２Ｏ２＋２Ｈ＋
（カソード）２Ｈ＋＋２ｅ−→Ｈ２
（ｈ＋：正孔、ｅ−：電子）
In general, in a water splitting reaction apparatus that separately collects hydrogen gas and oxygen gas, a two-electrode system including a photocatalytic electrode and a counter electrode is used. In the decomposition reaction of water in a two-electrode system, the following reaction proceeds on each electrode in an acidic solution.
(Anode) H 2 O + 2h + → 1 / 2O 2 + 2H +
(Cathode) 2H + + 2e − → H 2
(H + : hole, e − : electron)
また、中性溶液中では、各々の電極上で以下の反応が進行している。
（アノード）Ｈ２Ｏ＋２ｈ＋→１／２Ｏ２＋２Ｈ＋
（カソード）２Ｈ２Ｏ＋２ｅ−→Ｈ２＋２ＯＨ−
Further, in the neutral solution, the following reaction proceeds on each electrode.
(Anode) H 2 O + 2h + → 1 / 2O 2 + 2H +
(Cathode) 2H 2 O + 2e − → H 2 + 2OH −
また、塩基性溶液中では、各々の電極上で以下の反応が進行している。
（アノード）２ＯＨ−＋２ｈ＋→１／２Ｏ２＋Ｈ２Ｏ
（カソード）２Ｈ２Ｏ＋２ｅ−→Ｈ２＋２ＯＨ−
In the basic solution, the following reaction proceeds on each electrode.
(Anode) 2OH − + 2h + → 1 / 2O 2 + H 2 O
(Cathode) 2H 2 O + 2e − → H 2 + 2OH −
このとき、光励起された触媒表面の電子（ｅ−）もしくは正孔（ｈ＋）と反応物質とが、いかに効率よく関与するかということと、電子と正孔との再結合を抑制し、生成した電子をいかに対極側へ効率よく誘導するかということが重要である。特に光触媒粒子間抵抗や光触媒粒子−支持体間の抵抗は電子伝導を阻害するため、これを可能な限り低減する必要がある。以下、光触媒粒子間抵抗や光触媒粒子−支持体間の抵抗を低下させることができ、光電変換効率を向上させることができる、本発明の光水分解反応用電極について説明する。 At this time, how efficiently the electrons (e − ) or holes (h + ) on the surface of the photoexcited catalyst and the reactants are involved, and the recombination of electrons and holes is suppressed and generated. It is important how to efficiently guide the generated electrons to the counter electrode side. In particular, the resistance between the photocatalyst particles and the resistance between the photocatalyst particles and the support impede electron conduction, and therefore it is necessary to reduce them as much as possible. Hereinafter, the photocatalytic particle electrode of the present invention that can reduce the resistance between photocatalyst particles and the resistance between the photocatalyst particles and the support and can improve the photoelectric conversion efficiency will be described.
＜光水分解反応用電極＞
本発明の光水分解反応用電極の構成について説明する。
図１に本発明の光水分解反応用電極の一実施形態の拡大断面図を模式的に示す。本発明の光水分解反応用電極は、光触媒粒子１０、支持体２０、ならびに、光触媒粒子間および光触媒粒子−支持体間に付与した半導体または良導体３０で構成される。
<Photo water splitting electrode>
The structure of the electrode for photohydrolysis reaction of the present invention will be described.
FIG. 1 schematically shows an enlarged cross-sectional view of an embodiment of the electrode for photohydrolysis reaction of the present invention. The electrode for photohydrolysis reaction of the present invention comprises the photocatalyst particles 10, the support 20, and the semiconductor or good conductor 30 provided between the photocatalyst particles and between the photocatalyst particles and the support.
（光触媒粒子１０）
光触媒粒子１０を構成する光触媒としては、次の条件を満たしていればいかなる化合物でもよい。（１）光照射によって生成する電子の電位が水素イオンもしくは水分子を水素分子に還元できる電位よりも負であること、もしくは光照射によって生成する正孔の電位が水もしくは水酸化物イオンを酸素分子に酸化できる電位よりも正であること。（２）光触媒が水溶液中で光照射され、水分解反応が進行しても安定であること。光触媒粒子１０の粒子径は、その性能を発揮するものであれば特に限定されるものではないが、通常１ｎｍ以上であり、好ましくは１０ｎｍ以上であり、通常１００μｍ以下であり、好ましくは１０μｍ以下である。
(Photocatalyst particles 10)
The photocatalyst constituting the photocatalyst particle 10 may be any compound as long as the following conditions are satisfied. (1) The potential of electrons generated by light irradiation is more negative than the potential at which hydrogen ions or water molecules can be reduced to hydrogen molecules, or the potential of holes generated by light irradiation is oxygen in water or hydroxide ions. Be more positive than the potential that can be oxidized to a molecule. (2) The photocatalyst is stable even if it is irradiated with light in an aqueous solution and the water splitting reaction proceeds. The particle diameter of the photocatalyst particle 10 is not particularly limited as long as it exhibits its performance, but is usually 1 nm or more, preferably 10 nm or more, usually 100 μm or less, preferably 10 μm or less. is there.
水素イオンもしくは水を還元する、水素発生側の光触媒としては、具体的には、Ｃｒ、Ｓｂ、Ｔａ、Ｒｈ等をドープしたＳｒＴｉＯ３、Ｃｒ、Ｆｅ等をドープしたＬａＴｉ２Ｏ７、ＳｎＮｂ２Ｏ６などの酸化物；ＬａＴｉＯ２Ｎ、ＴａＯＮ、Ｔａ３Ｎ５、ＣａＴａＯ２Ｎ、ＳｒＴａＯ２Ｎ、ＢａＴａＯ２Ｎ、ＬａＴａＯ２Ｎ、Ｙ２Ｔａ２Ｏ５Ｎ２、ＧａＮ、ＭｇをドープしたＧａＮ、Ｇｅ３Ｎ４、Ｚｎ１＋ｘＧｅＮ２Ｏｘ、Ｇａ１−ｘＺｎｘＮ１−ｘＯｘ（ｘは、０〜１の数値を表す。）などのオキシナイトライドもしくはナイトライド化合物；や、ＺｎＳ、Ｃｕ、Ｎｉ、ＰｂをドープしたＺｎＳ、ＡｇをドープしたＣｄＳ、ＣｄｘＺｎ１−ｘＳ（ｘは、０〜１の数値を表す。）、ＣｕＩｎＳ２、ＣｕＩｎ５Ｓ８、ＣｕＧａ５Ｓ８、ＣｕＧａＳ２、ＡｇＧａＳ２、ＡｇＧａ０．９Ｉｎ０．１Ｓ２、ＡｇＩｎ５Ｓ８、ＮａＩｎＳ２、ＡｇＩｎＺｎ７Ｓ９、ＣｕＩｎＧａＳ２、Ｃｕ０．０９Ｉｎ０．０９Ｚｎ１．８２Ｓ２、Ｃｕ０．２５Ａｇ０．２５Ｉｎ０．５ＺｎＳ２、Ｃｕ２ＺｎＳｎＳ４などのサルファイド化合物；Ｓｍ２Ｔｉ２Ｏ５Ｓ２などのオキシサルファイド化合物；Ｌａ、Ｉｎを含むオキシサルファイド化合物（Ｃｈｅｍｉｓｔｒｙ Ｌｅｔｔｅｒｓ ２００７， ３６， ８５４−８５５）、ＣｕＩｎＧａＳｅ２、などのセレナイドを挙げることができるが、例示した材料に限定されるものではない。 As a photocatalyst on the hydrogen generation side that reduces hydrogen ions or water, specifically, SrTiO 3 doped with Cr, Sb, Ta, Rh, etc., LaTi 2 O 7 doped with Cr, Fe, etc., SnNb 2 O Oxides such as 6 ; LaTiO 2 N, TaON, Ta 3 N 5 , CaTaO 2 N, SrTaO 2 N, BaTaO 2 N, LaTaO 2 N, Y 2 Ta 2 O 5 N 2 , GaN doped with Mg, GaN, Oxynitride or nitride compounds such as Ge 3 N 4 , Zn 1 + x GeN 2 O x , Ga 1-x Zn x N 1-x O x (x represents a numerical value of 0 to 1 ); and ZnS ZnS doped with Cu, Ni, Pb, CdS doped with Ag, Cd x Zn 1-x S (x represents a numerical value of 0 to 1 ), CuInS 2 , Cu In 5 S 8 , CuGa 5 S 8 , CuGaS 2 , AgGaS 2 , AgGa 0.9 In 0.1 S 2 , AgIn 5 S 8 , NaInS 2 , AgInZn 7 S 9 , CuInGaS 2 , Cu 0.09 In 0. 09 Sulfide compounds such as Zn 1.82 S 2 , Cu 0.25 Ag 0.25 In 0.5 ZnS 2 , Cu 2 ZnSnS 4 ; Oxysulfide compounds such as Sm 2 Ti 2 O 5 S 2 ; La, In Examples thereof include selenides such as oxysulfide compounds (Chemistry Letters 2007, 36, 854-855) and CuInGaSe 2 , but are not limited to the exemplified materials.
水分子もしくは水酸化物イオンを酸素分子に酸化する、酸素発生側の光触媒としては、具体的にはＣｒ、Ｎｉ、Ｓｂ、Ｎｂ、Ｔｈ、Ｓｂ等をドープしたＴｉＯ２やＷＯ３、Ｂｉ２ＷＯ６、Ｂｉ２ＭｏＯ６、Ｉｎ２Ｏ３（ＺｎＯ）３、ＰｂＢｉ２Ｎｂ２Ｏ９、ＢｉＶＯ４、Ａｇ３ＶＯ４、ＡｇＬｉ１／３Ｔｉ２／３Ｏ２、ＡｇＬｉ１／３Ｓｎ２／３Ｏ２などの酸化物のほか、ＬａＴｉＯ２Ｎ、ＣａＮｂＯ２Ｎ、ＴａＯＮ、Ｔａ３Ｎ５、ＣａＴａＯ２Ｎ、ＳｒＴａＯ２Ｎ、ＢａＴａＯ２Ｎ、ＬａＴａＯ２Ｎ、Ｙ２Ｔａ２Ｏ５Ｎ２、ＧａＮ、ＭｇをドープしたＧａＮ、Ｇｅ３Ｎ４、Ｚｎ１＋ｘＧｅＮ２Ｏｘ、Ｇａ１−ｘＺｎｘＮ１−ｘＯｘ（ｘは、０〜１の数値を表す。）などのオキシナイトライドもしくはナイトライド化合物や、Ｓｍ２Ｔｉ２Ｏ５Ｓ２などのオキシサルファイド化合物を用いることができるが、例示した材料に限定されるものではない。 As a photocatalyst on the oxygen generation side that oxidizes water molecules or hydroxide ions to oxygen molecules, specifically, TiO 2 doped with Cr, Ni, Sb, Nb, Th, Sb, etc., WO 3 , Bi 2 WO 6 , Bi 2 MoO 6 , In 2 O 3 (ZnO) 3 , PbBi 2 Nb 2 O 9 , BiVO 4 , Ag 3 VO 4 , AgLi 1/3 Ti 2/3 O 2 , AgLi 1/3 Sn 2/3 other oxides, such as O 2, LaTiO 2 N, CaNbO 2 N, TaON, Ta 3 N 5, CaTaO 2 N, SrTaO 2 N, BaTaO 2 N, LaTaO 2 N, Y 2 Ta 2 O 5 N 2, GaN , GaN doped with Mg, Ge 3 N 4 , Zn 1 + x GeN 2 O x , Ga 1-x Zn x N 1-x O x (x represents a numerical value of 0 to 1 ) and the like. Although it is possible to use an itide or nitride compound or an oxysulfide compound such as Sm 2 Ti 2 O 5 S 2 , the material is not limited to the exemplified materials.
光触媒としては、オキシナイトライド、ナイトライド、オキシサルファイド、および、サルファイドからなる群から選ばれる１種以上の光触媒、中でも、ＬａＴｉＯ２Ｎ、ＣａＮｂＯ２Ｎ、Ｇａ１−ｘＺｎｘＮ１−ｘＯｘ（ｘは、０〜１の数値を表す。）、Ｃｕ２ＺｎＳｎＳ４を用いることが、光触媒活性が高いこと、地上における存在量が豊富であること、価格が低い点から好ましい。
上記した光触媒は、従来の公知の方法（例えば、Ｊ．Ｐｈｙｓ．Ｃｈｅｍ．Ｂ ２００３，１０７，７９１−７９７）により合成することができる。
As a photocatalyst, at least one photocatalyst selected from the group consisting of oxynitride, nitride, oxysulfide, and sulfide, among them, LaTiO 2 N, CaNbO 2 N, Ga 1-x Zn x N 1-x O It is preferable to use x (x represents a numerical value of 0 to 1) and Cu 2 ZnSnS 4 because of high photocatalytic activity, abundant abundance on the ground, and low cost.
The above-described photocatalyst can be synthesized by a conventionally known method (for example, J. Phys. Chem. B 2003, 107, 791-797).
上記光触媒には、必要に応じて助触媒を使用することができる。水素発生側の光触媒の助触媒としては、具体的にはＰｔ、Ｐｄ、Ｒｈ、Ｒｕ、Ｎｉ、Ａｕ、Ｆｅ、ＮｉＯ、ＲｕＯ２、およびＣｒ‐Ｒｈ酸化物等を挙げることができる。酸素発生側の光触媒の助触媒としては、具体的にはＩｒＯ２、Ｐｔ、Ｃｏ、Ｆｅ、Ｃ、Ｎｉ、Ａｇ、ＣｏＯ、Ｃｏ３Ｏ４等を挙げることができるが、例示した材料に限定されるものではない。 A cocatalyst can be used for the photocatalyst as needed. Specific examples of the cocatalyst for the photocatalyst on the hydrogen generation side include Pt, Pd, Rh, Ru, Ni, Au, Fe, NiO, RuO 2 , and Cr—Rh oxide. Specific examples of the cocatalyst for the photocatalyst on the oxygen generation side include IrO 2 , Pt, Co, Fe, C, Ni, Ag, CoO, and Co 3 O 4, but are limited to the exemplified materials. It is not something.
（支持体２０）
支持体２０としては、金属または非金属の支持体を用いることができる。また、支持体２０としては、金属、あるいは、カーボン（グラファイト）または酸化物伝導体等の非金属の導電材料により形成された導電性支持体を用いることが好ましい。中でも、良好な加工性を有することから、金属支持体を用いることが特に好ましい。金属支持体としては、良好な電気伝導性を示す元素の単体、もしくは合金を用いることができる。元素の単体とは、具体的にはＡｌ、Ａｕ、Ｃｕ、Ｍｏ、Ｎｉ、Ｐｄ、Ｐｔ、Ｔｉ、Ｗなどを挙げることができる。一方合金とは、具体的にはステンレス鋼、炭素鋼、チタン合金、アルミニウム合金などを挙げることができるが、例示した材料に限定されるものではない。中でも、電解質溶液中において、広いｐＨ範囲で安定であり、高い電気伝導性を示す点から、金属支持体としては、チタン、チタン合金、または、チタンもしくはチタン合金を表面にコートした金属を用いることが好ましい。
(Support 20)
As the support 20, a metal or non-metal support can be used. The support 20 is preferably a conductive support formed of a metal or a non-metallic conductive material such as carbon (graphite) or an oxide conductor. Among them, it is particularly preferable to use a metal support because it has good workability. As the metal support, a simple substance or an alloy of an element exhibiting good electrical conductivity can be used. Specific examples of the elemental element include Al, Au, Cu, Mo, Ni, Pd, Pt, Ti, and W. On the other hand, specific examples of the alloy include stainless steel, carbon steel, titanium alloy, and aluminum alloy, but are not limited to the exemplified materials. Above all, titanium, titanium alloy, or metal coated on the surface of titanium or titanium alloy is used as the metal support because it is stable in an electrolyte solution in a wide pH range and exhibits high electrical conductivity. Is preferred.
支持体２０の形状としては、光触媒粒子１０を表面に堆積できる形状であれば特に限定されないが、生成イオンを対極に迅速に輸送する必要がある点から、パンチングメタル状、メッシュ状、格子状、または、貫通した細孔を持つ多孔体のいずれかであることが好ましい。 The shape of the support 20 is not particularly limited as long as the photocatalyst particles 10 can be deposited on the surface, but from the point that it is necessary to quickly transport the generated ions to the counter electrode, a punching metal shape, a mesh shape, a lattice shape, Or it is preferable that it is either the porous body which has the through-hole.
（半導体または良導体３０）
半導体または良導体３０としては、良好な電気伝導性を示し、かつ水分解反応の逆反応や光触媒の水分解反応の対となる反応を触媒しない材料を使用することができる。具体的には、ＴｉＮ、ＴｉＯ２、Ｔａ３Ｎ５、ＴａＯＮ、ＺｎＯ、ＳｎＯ２、ＩＴＯ、Ａｇ、Ａｕ、Ｃ、Ｃｕ、Ｃｄ、Ｃｏ、Ｃｒ、Ｆｅ、Ｇａ、Ｇｅ、Ｈｇ、Ｉｒ、Ｉｎ、Ｍｎ、Ｍｏ、Ｎｉ、Ｎｂ、Ｐｂ、Ｒｕ、Ｒｅ、Ｒｈ、Ｓｎ、Ｓｂ、Ｔａ、Ｔｉ、Ｖ、Ｗ、並びに、これらの合金および混合物が挙げられるが、例示した材料に限定されるものではない。
(Semiconductor or good conductor 30)
As the semiconductor or the good conductor 30, a material that exhibits good electrical conductivity and does not catalyze a reaction that is a reverse reaction of a water splitting reaction or a water splitting reaction of a photocatalyst can be used. Specifically, TiN, TiO 2, Ta 3 N 5, TaON, ZnO, SnO 2, ITO, Ag, Au, C, Cu, Cd, Co, Cr, Fe, Ga, Ge, Hg, Ir, In, Examples include Mn, Mo, Ni, Nb, Pb, Ru, Re, Rh, Sn, Sb, Ta, Ti, V, W, and alloys and mixtures thereof, but are not limited to the exemplified materials. .
また、伝導帯のエネルギー準位をなるべく近接させて電子移動をスムーズに行わせる点から、半導体または良導体３０と支持体２０とは、同一の元素を含んでいることが好ましい。また、支持体２０としては、チタン、チタン合金、または、チタン若しくはチタン合金を表面にコートした金属のいずれかを用いることが好ましく、半導体または良導体３０もチタンを含む材料であることが好ましい。中でも、チタンを含む材料としては、良好な電子伝導性を持つ点からＴｉＮを用いることが好ましい。 Moreover, it is preferable that the semiconductor or the good conductor 30 and the support 20 contain the same element from the viewpoint that the energy level of the conduction band is as close as possible and the electron transfer is performed smoothly. The support 20 is preferably made of titanium, a titanium alloy, or a metal whose surface is coated with titanium or a titanium alloy, and the semiconductor or the good conductor 30 is also preferably a material containing titanium. Among these, TiN is preferably used as a material containing titanium from the viewpoint of having good electron conductivity.
また、それぞれの光触媒に相性の良い半導体または良導体３０があり、例えば、光触媒として、Ｔｉ、Ｎを含むもの（例えば、ＬａＴｉＯ２Ｎ）を用いた場合は、半導体または良導体３０としては、ＴｉＮ、ＴｉＯ２、ＴｉＯ２−ｘＮｘ（ｘは０〜２の数値を表す。
）が好適に用いられる。
Further, each photocatalyst has a compatible semiconductor or good conductor 30. For example, when a photocatalyst containing Ti or N (for example, LaTiO 2 N) is used, the semiconductor or good conductor 30 may be TiN or TiO. 2 , TiO 2-x N x (x represents a numerical value of 0-2).
) Is preferably used.
（光水分解反応用電極の製法）
次に、本発明の光水分解反応用電極の製造方法について説明する。なお、以下に示す製造方法は、あくまで本発明の電極を製造するための方法の一実施形態であって、他の方法を排除する趣旨ではない。
支持体２０は、機械的研磨、洗浄の後、光触媒粒子１０を堆積する。光触媒粒子１０の堆積には、真空蒸着法やスパッタリング法などの気相成長法、ゾルゲル法、塗布法、電気泳動電着法などを使用することができる。ここで、「堆積」とは、実質的に光触媒粒子の平均粒径の大きさ以上の厚みをもって積層することをいう。
(Production method of electrode for photo-water splitting reaction)
Next, the manufacturing method of the electrode for photohydrolysis reaction of this invention is demonstrated. In addition, the manufacturing method shown below is one Embodiment for the method for manufacturing the electrode of this invention to the last, Comprising: It is not the meaning which excludes another method.
The support 20 deposits the photocatalyst particles 10 after mechanical polishing and cleaning. For the deposition of the photocatalyst particles 10, a vapor phase growth method such as a vacuum evaporation method or a sputtering method, a sol-gel method, a coating method, an electrophoretic electrodeposition method, or the like can be used. Here, “deposition” refers to stacking with a thickness substantially equal to or larger than the average particle diameter of the photocatalyst particles.
光触媒粒子を堆積した電極は、空気中、５０℃〜５００℃程度で数分間乾燥させた後、半導体または良導体３０の前躯体溶液に電極全体を数秒間浸漬する。その後、再び電極を空気中で５０℃〜５００℃程度で数秒間〜数分間乾燥する。この前駆体溶液への浸漬および空気中での乾燥を１０回〜数１０回繰り返す。このようにして十分な量の半導体または良導体３０の前駆体で光触媒粒子および支持体表面をコーティングした後、熱分解処理を行う。このようにして、光触媒粒子間ならびに光触媒粒子−支持体間に、半導体または良導体３０を付与する。なお、使用する光触媒粒子１０、ならびに、半導体または良導体３０に応じて、半導体または良導体の前駆体および熱処理方法は異なる。 The electrode on which the photocatalyst particles are deposited is dried in air at about 50 ° C. to 500 ° C. for several minutes, and then the entire electrode is immersed in the precursor solution of the semiconductor or good conductor 30 for several seconds. Thereafter, the electrode is again dried in air at about 50 ° C. to 500 ° C. for several seconds to several minutes. The immersion in the precursor solution and the drying in the air are repeated 10 times to several tens of times. After coating the photocatalyst particles and the support surface with a sufficient amount of the semiconductor or the precursor of the good conductor 30 in this way, a thermal decomposition treatment is performed. In this way, the semiconductor or good conductor 30 is applied between the photocatalyst particles and between the photocatalyst particles and the support. The precursor of the semiconductor or good conductor and the heat treatment method differ depending on the photocatalyst particles 10 and the semiconductor or good conductor 30 to be used.
例えば、光触媒粒子１０としてＬａＴｉＯ２Ｎ粒子を使用し、半導体または良導体３０としてＴｉＮを使用する場合、支持体２０にＬａＴｉＯ２Ｎ粒子を堆積させた後、該電極をＴｉＣｌ４のメタノール溶液（半導体または良導体の前駆体溶液）に浸漬させ、空気中で乾燥させる。この処理を数回繰り返し、ＬａＴｉＯ２Ｎ／支持体からなる電極上にＴｉＣｌ４を吸着させる。その後、この電極を、８００℃、ＮＨ３気流下で窒化処理を行い、ＴｉＣｌ４をＴｉＮとする。これにより、ＬａＴｉＯ２Ｎ／ＴｉＮ／支持体からなる本発明の電極が製造される。 For example, when LaTiO 2 N particles are used as the photocatalyst particles 10 and TiN is used as the semiconductor or good conductor 30, LaTiO 2 N particles are deposited on the support 20, and then the electrode is attached to a methanol solution of TiCl 4 (semiconductor or It is immersed in a precursor solution of a good conductor and dried in air. This process is repeated several times, and TiCl 4 is adsorbed on the electrode made of LaTiO 2 N / support. Thereafter, this electrode is subjected to nitriding treatment at 800 ° C. under an NH 3 gas stream to change TiCl 4 into TiN. Thereby, the electrode of the present invention consisting of LaTiO 2 N / TiN / support is produced.
半導体または良導体３０を付与する量は、光触媒粒子１０の光触媒作用を阻害せず、それでいて光触媒粒子間および光触媒粒子−支持体間の抵抗を減ずるに十分な最適値とすることが好ましい。具体的には、堆積された光触媒粒子１０の量に対し、質量比で１％〜５００％、好ましくは２％〜２２０％である。 The amount of the semiconductor or the good conductor 30 is preferably set to an optimum value sufficient to reduce the resistance between the photocatalyst particles and between the photocatalyst particles and the support without inhibiting the photocatalytic action of the photocatalyst particles 10. Specifically, the mass ratio is 1% to 500%, preferably 2% to 220% with respect to the amount of the deposited photocatalyst particles 10.
（実施例１）
Ｌａ（ＮＯ３）３・６Ｈ２Ｏ、Ｔｉ（Ｏ−ｉＰｒ）４、クエン酸、エチレングリコールをメタノール中、モル比１：１：１０：３０となるように混合し、３７３Ｋで重合させた。さらに６２３Ｋで熱処理して炭化させた後、空気中９２３Ｋで焼成しＬａとＴｉの複合酸化物前駆体を得た。この前駆体を１００ｍＬ／分のＮＨ３気流下で１Ｋ／分で１１２３Ｋまで昇温したのちこの温度で１５時間保ち、その後室温まで冷却してＬａＴｉＯ２Ｎを合成した。得られたＬａＴｉＯ２Ｎ粉末とアセトン、ヨウ素の懸濁液を調製し、これにＴｉメッシュを浸漬、ＦＴＯ（フッ素ドープ酸化スズ）を対極として１０Ｖの電圧を１分間付加することにより、ＬａＴｉＯ２Ｎ／Ｔｉ電極を調製した。
Example 1
La (NO 3) 3 · 6H 2 O, Ti (O-iPr) 4, in the citric acid, ethylene glycol, methanol, molar ratio 1: 1: 10: 30 were mixed so that, was polymerized 373 K. Further, after heat treatment at 623K and carbonization, firing was performed in air at 923K to obtain a composite oxide precursor of La and Ti. This precursor was heated to 1123 K at 1 K / min under an NH 3 gas stream of 100 mL / min, then kept at this temperature for 15 hours, and then cooled to room temperature to synthesize LaTiO 2 N. A suspension of the obtained LaTiO 2 N powder, acetone, and iodine was prepared, a Ti mesh was immersed in this, and a voltage of 10 V was applied for 1 minute using FTO (fluorine-doped tin oxide) as a counter electrode, whereby LaTiO 2 N / Ti electrode was prepared.
さらにこのＬａＴｉＯ２Ｎ／Ｔｉ電極を２０ｍＭ ＴｉＣｌ４／メタノール溶液に５秒間浸漬、空気中２５０℃で１分間乾燥させる、浸漬および乾燥処理を数回繰り返し、ＬａＴｉＯ２Ｎ／Ｔｉ表面上にＴｉＣｌ４を吸着させた。このＴｉＣｌ４を吸着させた電極を８００℃、１００ｍＬ／分のＮＨ３気流下で１時間窒化処理を行って、ＬａＴｉＯ２Ｎの光触媒粒子が、Ｔｉ支持体上に堆積されてなり、光触媒粒子間ならびに光触媒粒子およびＴｉ支持体間にＴｉＮを有している本発明の電極（ＬａＴｉＯ２Ｎ／ＴｉＮ／Ｔｉ電極）を得た。 Further, this LaTiO 2 N / Ti electrode was immersed in a 20 mM TiCl 4 / methanol solution for 5 seconds and dried in air at 250 ° C. for 1 minute. The immersion and drying processes were repeated several times, and TiCl 4 was deposited on the LaTiO 2 N / Ti surface. Adsorbed. This electrode on which TiCl 4 was adsorbed was subjected to nitriding treatment at 800 ° C. under an NH 3 stream of 100 mL / min for 1 hour, and LaTiO 2 N photocatalyst particles were deposited on the Ti support. In addition, an electrode of the present invention (LaTiO 2 N / TiN / Ti electrode) having TiN between the photocatalyst particles and the Ti support was obtained.
図２に光電流を測定するための光電気化学セルの模式図を示す。参照電極５４としてＡｇ／ＡｇＣｌを使用し、電解質溶液５６として０．１Ｍ Ｎａ２ＳＯ４水溶液（ｐＨ＝６）を使用した。カットフィルター５２を介して光源５１から、ＬａＴｉＯ２Ｎ／ＴｉＮ／Ｔｉメッシュ５３に光を当て、発生する光電流を測定した。 FIG. 2 shows a schematic diagram of a photoelectrochemical cell for measuring photocurrent. Ag / AgCl was used as the reference electrode 54, and 0.1 M Na 2 SO 4 aqueous solution (pH = 6) was used as the electrolyte solution 56. Light was applied to the LaTiO 2 N / TiN / Ti mesh 53 from the light source 51 through the cut filter 52, and the generated photocurrent was measured.
図３にＴｉＣｌ４溶液への浸漬回数と、生成するＬａＴｉＯ２Ｎ／ＴｉＮ／Ｔｉ電極の０．６Ｖ ｖｓ．Ａｇ／ＡｇＣｌにおける光電流密度（図２の装置で測定したもの。）との関係を示す。図３より、ＴｉＮの付与によって電極内部抵抗が減少して光電流密度が向上することが示された。浸漬回数０回のものでは、光電流密度は２３μＡ／ｃｍ２であったが、浸漬回数３０回のものでは、光電流密度は７５μＡ／ｃｍ２と３倍以上も向上した。また、光電流密度は、浸漬回数が少ない場合は、浸漬回数に比例して増加するが、浸漬回数が増えると光電流密度は飽和する傾向がある。よって、光電流密度を向上させるための、最適な浸漬回数は２０回〜３０回であることが分かった。 FIG. 3 shows the number of immersions in the TiCl 4 solution and the resulting LaTiO 2 N / TiN / Ti electrode 0.6 V vs. The relationship with the photocurrent density (measured with the apparatus of FIG. 2) in Ag / AgCl is shown. FIG. 3 shows that application of TiN reduces the internal resistance of the electrode and improves the photocurrent density. When the number of immersions was 0, the photocurrent density was 23 μA / cm 2 , but when the number of immersions was 30 times, the photocurrent density was 75 μA / cm 2, which was improved by 3 times or more. Further, the photocurrent density increases in proportion to the number of immersions when the number of immersions is small, but the photocurrent density tends to be saturated when the number of immersions increases. Therefore, it was found that the optimal number of immersions for improving the photocurrent density is 20 to 30 times.
図４と図５にＬａＴｉＯ２Ｎ／Ｔｉ電極およびＬａＴｉＯ２Ｎ／ＴｉＮ／Ｔｉ電極表面の走査型電子顕微鏡写真を示す。図４（ａ）は、ＴｉＣｌ４溶液で処理していない電極（ＬａＴｉＯ２Ｎ／Ｔｉ電極）である。もとのＴｉメッシュ電極（触媒堆積前）の線径は１００μｍであり、図４（ａ）で観測された線径は約１０８〜１０９μｍ前後であることから、触媒の堆積量は約８〜９μｍである。（ｂ）がＴｉＣｌ４溶液への浸漬−乾燥を１０回繰り返して１時間窒化処理を行った後の電極で、線径は約１１４μｍ、（ｃ）がＴｉＣｌ４溶液への浸漬−乾燥を２０回繰り返して１時間窒化処理を行った後の電極で、線径は約１１１μｍ、（ｄ）がＴｉＣｌ４溶液への浸漬−乾燥を３０回繰り返して１時間窒化処理を行った後の電極で、線径は約１２０μｍである。図４（ａ）〜（ｄ）は、それぞれ２５０倍の拡大写真である。数値の前後はあるが、全体の傾向として、浸漬回数が増えるごとに電極網の直径が増大していることが明らかである。 4 and 5 show scanning electron micrographs of the surfaces of the LaTiO 2 N / Ti electrode and the LaTiO 2 N / TiN / Ti electrode. FIG. 4A shows an electrode not treated with a TiCl 4 solution (LaTiO 2 N / Ti electrode). Since the original Ti mesh electrode (before catalyst deposition) has a wire diameter of 100 μm and the wire diameter observed in FIG. 4A is about 108 to 109 μm, the amount of catalyst deposited is about 8 to 9 μm. It is. (B) Electrode after nitriding for 10 hours by repeating immersion-drying in TiCl 4 solution 10 times, wire diameter is about 114 μm, (c) 20 times immersion-drying in TiCl 4 solution The electrode after the nitriding treatment was repeated for 1 hour, the wire diameter was about 111 μm, and (d) was immersed in a TiCl 4 solution and dried 30 times, and the electrode after the nitriding treatment for 1 hour was performed. The diameter is about 120 μm. 4A to 4D are magnified photographs of 250 times. Although it is before and after the numerical value, as a whole, it is clear that the diameter of the electrode network increases as the number of immersions increases.
図５（ａ）は、ＴｉＣｌ４溶液で処理していない電極（ＬａＴｉＯ２Ｎ／Ｔｉ電極）であり、（ｂ）はＴｉＣｌ４溶液への浸漬−乾燥を３０回繰り返して１時間窒化処理を行った後の電極である。図５（ａ）は３０００倍の拡大写真であり、（ｂ）は５０００倍の拡大写真である。 FIG. 5A shows an electrode not treated with a TiCl 4 solution (LaTiO 2 N / Ti electrode), and FIG. 5B shows nitriding treatment by repeating immersion-drying in the TiCl 4 solution 30 times for 1 hour. It is an electrode after. FIG. 5A is an enlarged photograph of 3000 times, and FIG. 5B is an enlarged photograph of 5000 times.
図４、５より、ＴｉＣｌ４／ＮＨ３処理によりＬａＴｉＯ２Ｎ粒子間がＴｉＮにより補完されていることが見て取れ、これによって電極内部抵抗が低下したと推測される。 4 and 5, it can be seen that the TiTiO 4 N particles are complemented by TiN by the TiCl 4 / NH 3 treatment, and it is presumed that the internal resistance of the electrode has decreased.
図６にＬａＴｉＯ２Ｎ／Ｔｉ電極（ＴｉＣｌ４浸漬処理なし、ＮＨ３処理のみ、下のグラフ）およびＬａＴｉＯ２Ｎ／ＴｉＮ／Ｔｉ電極（ＴｉＣｌ４／ＮＨ３処理あり、ＴｉＣｌ４処理回数：２０回、上のグラフ）の印加電圧に対する光電流密度依存性を観測した結果を示す。光電流密度はＴｉＣｌ４／ＮＨ３処理をすると、処理をしない場合に比較して著しく向上した。また、ＴｉＣｌ４／ＮＨ３処理を施したＬａＴｉＯ２Ｎ／ＴｉＮ／Ｔｉ電極の電流が流れ始める電圧は可逆水素電極（ＲＨＥ）よりも負側（カソード側）であることから、光触媒であるＬａＴｉＯ２Ｎを堆積する電極として金属電極であるＴｉを選択したことにより、エネルギー準位のミスマッチによる光触媒−電極間の抵抗を低減できることが明らかになった。なおＴｉＣｌ４／ＮＨ３処理を施さないＬａＴｉＯ２Ｎ／Ｔｉにおいても電流値は小さいもののＲＨＥよりも負側から電流が流れ始めることから、光触媒−電極間の抵抗を低減するためには、ＴｉＣｌ４／ＮＨ３処理にかかわりなく、ＬａＴｉＯ２Ｎとマッチングのよい半導体電極、もしくは導電性の高い金属電極を選択すればよいことが分かる。 FIG. 6 shows a LaTiO 2 N / Ti electrode (without TiCl 4 immersion treatment, NH 3 treatment only, lower graph) and a LaTiO 2 N / TiN / Ti electrode (with TiCl 4 / NH 3 treatment, number of TiCl 4 treatments: 20 times) The graph shows the result of observing the dependence of the photocurrent density on the applied voltage in the upper graph). The photocurrent density was remarkably improved when the TiCl 4 / NH 3 treatment was performed compared to the case where the treatment was not performed. Moreover, since the voltage at which the current of the LaTiO 2 N / TiN / Ti electrode subjected to the TiCl 4 / NH 3 treatment starts to flow is more negative (cathode side) than the reversible hydrogen electrode (RHE), LaTiO 2 that is a photocatalyst. It has been clarified that the resistance between the photocatalyst and the electrode due to energy level mismatch can be reduced by selecting Ti as a metal electrode as an electrode for depositing N. In LaTiO 2 N / Ti not subjected to TiCl 4 / NH 3 treatment, the current starts to flow from the negative side of RHE, although the current value is small. Therefore, in order to reduce the resistance between the photocatalyst and the electrode, TiCl 4 It can be seen that, regardless of the / NH 3 treatment, a semiconductor electrode having good matching with LaTiO 2 N or a metal electrode having high conductivity may be selected.
図７にＬａＴｉＯ２Ｎ／ＴｉＮ／Ｔｉ電極（ＴｉＣｌ４処理回数：２０回、下側のグラフ）およびＩｒＯ２／ＬａＴｉＯ２Ｎ／ＴｉＮ／Ｔｉ電極（上側のグラフ）の印加電圧に対する光電流密度依存性を観測した結果を示す。光電流密度は助触媒であるＩｒＯ２の存在で著しく向上した。なお、酸化イリジウム処理は、ＬａＴｉＯ２Ｎ／ＴｉＮ／Ｔｉ電極（下側のグラフのもの）を、酸化イリジウムコロイド溶液に一回浸漬、乾燥することにより、行った。なお、酸化イリジウムコロイド溶液は、水２０ｍｌ中にＮａ２ＩｒＣｌ６を５０ｍｇ溶かし、ＮａＯＨを添加してｐＨ１２にしたのち、ウオーターバス中で８０℃まで加熱する。溶液の色が茶色から透明に変わり、最後にはダークブルーになったところで加熱をやめ、溶液を放冷することで調製した。 FIG. 7 shows the dependence of photocurrent density on the applied voltage of LaTiO 2 N / TiN / Ti electrode (TiCl 4 treatment frequency: 20 times, lower graph) and IrO 2 / LaTiO 2 N / TiN / Ti electrode (upper graph). The result of having observed the sex is shown. The photocurrent density was remarkably improved in the presence of IrO 2 as a promoter. The iridium oxide treatment was performed by immersing and drying a LaTiO 2 N / TiN / Ti electrode (in the lower graph) once in an iridium oxide colloidal solution. The iridium oxide colloidal solution is prepared by dissolving 50 mg of Na 2 IrCl 6 in 20 ml of water, adding NaOH to pH 12, and then heating to 80 ° C. in a water bath. When the color of the solution changed from brown to transparent and finally dark blue, heating was stopped and the solution was allowed to cool.
図８に参考データとしてＬａＴｉＯ２ＮをＮｂ：ＳｒＴｉＯ３上にスパッタリングによって堆積した光触媒電極の光電流観測結果を示した（出典：非特許文献４）。上段のグラフが助触媒としてＩｒＯ２を添加した場合、下段のグラフはこれを添加しない場合である。電極として酸化物半導体を使用しているため、ＬａＴｉＯ２Ｎとのエネルギー準位にミスマッチが生じ、それが内部抵抗となって光電流の流れ始める電位はＲＨＥよりも正側である。また、図８の電極は、スパッタリングという欠陥の少なく均一で強固な薄膜を形成しうる手法で作製された電極であるが、この電極に比較して、本発明の電極は３倍程度の光電流密度を示した。なお、図６、７での光電流密度の単位は、ｍＡ／ｃｍ２であり、図８での単位はμＡ／ｃｍ２である。 FIG. 8 shows a photocurrent observation result of a photocatalyst electrode in which LaTiO 2 N is deposited on Nb: SrTiO 3 by sputtering as reference data (Source: Non-Patent Document 4). When IrO 2 is added as a promoter in the upper graph, the lower graph is when this is not added. Since an oxide semiconductor is used as an electrode, a mismatch occurs in the energy level with LaTiO 2 N, and the potential at which a photocurrent flows as a result of internal resistance is on the positive side of RHE. 8 is an electrode manufactured by a technique capable of forming a uniform and strong thin film with few defects called sputtering, but the electrode of the present invention has a photocurrent about three times that of this electrode. The density is shown. 6 and 7, the unit of photocurrent density is mA / cm 2 , and the unit in FIG. 8 is μA / cm 2 .
以上、現時点において、もっとも、実践的であり、かつ、好ましいと思われる実施形態に関連して本発明を説明したが、本発明は、本願明細書中に開示された実施形態に限定されるものではなく、請求の範囲および明細書全体から読み取れる発明の要旨或いは思想に反しない範囲で適宜変更可能であり、そのような変更を伴う光水分解反応用電極もまた本発明の技術的範囲に包含されるものとして理解されなければならない。 While the present invention has been described in connection with embodiments that are presently the most practical and preferred, the present invention is not limited to the embodiments disclosed herein. However, the electrode can be changed as appropriate without departing from the scope or spirit of the invention that can be read from the claims and the entire specification, and the electrode for photohydrolysis reaction with such a change is also included in the technical scope of the present invention. Must be understood as being.
本発明は、支持体上に光触媒を堆積させてなる光触媒電極の作製手法に新たな可能性を提供する。また、本発明の電極を利用して、光触媒に電位を印加することにより効率的に水分解を進行させるシステムを構築できる。本発明によると、光触媒電極を用いた効果的な水分解による水素製造技術が提供できる。 The present invention provides a new possibility for a method for producing a photocatalytic electrode in which a photocatalyst is deposited on a support. In addition, a system for efficiently proceeding with water splitting can be constructed by applying a potential to the photocatalyst using the electrode of the present invention. According to the present invention, a hydrogen production technique by effective water splitting using a photocatalytic electrode can be provided.
１０ 光触媒粒子
２０ 支持体
３０ 半導体または良導体
５１ 光源
５２ カットフィルター
５３ ＬａＴｉＯ２Ｎ／ＴｉＮ／Ｔｉメッシュ
５４ 参照電極
５５ 白金線
５６ ０．１Ｍ Ｎａ２ＳＯ４水溶液（ｐＨ＝６）
６１ 光触媒電極
６２ 隔膜もしくはイオン交換膜
６３ 対極
６４ 導体
６５ 電解質水溶液
10 photocatalyst particles 20 support 30 semiconductor or conductor 51 a light source 52 cut filter 53 LaTiO 2 N / TiN / Ti mesh 54 reference electrode 55 of platinum wire 56 0.1M Na 2 SO 4 aqueous solution (pH = 6)
61 Photocatalyst electrode 62 Membrane or ion exchange membrane 63 Counter electrode 64 Conductor 65 Electrolyte aqueous solution
Claims (5)
前記半導体または良導体が、ＴｉＮ、ＴｉＯ２、Ｔａ３Ｎ５、ＴａＯＮ、ＺｎＯ、ＳｎＯ２、ＩＴＯ、Ａｇ、Ａｕ、Ｃ、Ｃｕ、Ｃｄ、Ｃｏ、Ｃｒ、Ｆｅ、Ｇａ、Ｇｅ、Ｈｇ、Ｉｒ、Ｉｎ、Ｍｎ、Ｍｏ、Ｎｉ、Ｎｂ、Ｐｂ、Ｒｕ、Ｒｅ、Ｒｈ、Ｓｎ、Ｓｂ、Ｔａ、Ｔｉ、Ｖ、Ｗ、並びに、これらの合金および混合物から選ばれるいずれかであり、
前記半導体または良導体の前駆体溶液に前記光触媒粒子を浸漬して、該半導体または良導体の前駆体で該光触媒粒子をコーティングした後、熱分解処理を行うことを特徴とする、
光水分解反応用電極の製造方法。 As the photocatalyst constituting the photocatalyst particle, one or more selected from the group consisting of oxynitride, nitride, oxysulfide, and sulfide is deposited on a support, and a semiconductor or a good conductor is provided around the photocatalyst particle. Is a method for producing an electrode for water-splitting reaction,
The semiconductor or good conductor is TiN, TiO 2 , Ta 3 N 5 , TaON, ZnO, SnO 2 , ITO, Ag, Au, C, Cu, Cd, Co, Cr, Fe, Ga, Ge, Hg, Ir, In , Mn, Mo, Ni, Nb, Pb, Ru, Re, Rh, Sn, Sb, Ta, Ti, V, W, and alloys and mixtures thereof,
The photocatalyst particles are immersed in the semiconductor or good conductor precursor solution, the photocatalyst particles are coated with the semiconductor or good conductor precursor, and then subjected to a thermal decomposition treatment.
A method for producing an electrode for photohydrolysis reaction.
前記光触媒粒子間ならびに前記光触媒粒子および前記支持体間に半導体または良導体を有し、且つ、前記半導体または良導体が、ＴｉＮ、ＴｉＯ２、Ｔａ３Ｎ５、ＴａＯＮ、ＺｎＯ、ＳｎＯ２、ＩＴＯ、Ａｇ、Ａｕ、Ｃ、Ｃｕ、Ｃｄ、Ｃｏ、Ｃｒ、Ｆｅ、Ｇａ、Ｇｅ、Ｈｇ、Ｉｒ、Ｉｎ、Ｍｎ、Ｍｏ、Ｎｉ、Ｎｂ、Ｐｂ、Ｒｕ、Ｒｅ、Ｒｈ、Ｓｎ、Ｓｂ、Ｔａ、Ｔｉ、Ｖ、Ｗ、並びに、これらの合金および混合物から選ばれるいずれかであり、
前記半導体または良導体の前駆体で前記光触媒粒子および前記支持体表面をコーティングした後に熱処理を行うことにより、前記光触媒粒子間ならびに前記光触媒粒子および前記支持体間に半導体または良導体が付与されていることを特徴とする、
光水分解反応用電極。 As a photocatalyst constituting the photocatalyst particles, an electrode in which one or more selected from the group consisting of oxynitride, nitride, oxysulfide, and sulfide is deposited on a support,
Between the photocatalyst particles and between the photocatalyst particles and the support, the semiconductor or good conductor has TiN, TiO 2 , Ta 3 N 5 , TaON, ZnO, SnO 2 , ITO, Ag, Au, C, Cu, Cd, Co, Cr, Fe, Ga, Ge, Hg, Ir, In, Mn, Mo, Ni, Nb, Pb, Ru, Re, Rh, Sn, Sb, Ta, Ti, V, W, and any one of these alloys and mixtures,
The semiconductor or good conductor is provided between the photocatalyst particles and between the photocatalyst particles and the support by performing a heat treatment after coating the surface of the photocatalyst particles and the support with the precursor of the semiconductor or good conductor. Features
Electrode for photohydrolysis reaction.
前記光触媒粒子間ならびに前記光触媒粒子および前記支持体間に半導体または良導体を有し、且つ、前記半導体または良導体が、ＴｉＮ、ＴｉＯ２、Ｔａ３Ｎ５、ＴａＯＮ、ＺｎＯ、ＳｎＯ２、ＩＴＯ、Ａｇ、Ａｕ、Ｃ、Ｃｕ、Ｃｄ、Ｃｏ、Ｃｒ、Ｆｅ、Ｇａ、Ｇｅ、Ｈｇ、Ｉｒ、Ｉｎ、Ｍｎ、Ｍｏ、Ｎｉ、Ｎｂ、Ｐｂ、Ｒｕ、Ｒｅ、Ｒｈ、Ｓｎ、Ｓｂ、Ｔａ、Ｔｉ、Ｖ、Ｗ、並びに、これらの合金および混合物から選ばれるいずれかであり、
前記半導体または良導体の前駆体で前記光触媒粒子および前記支持体表面をコーティングした後に熱処理を行うことにより、前記光触媒粒子間ならびに前記光触媒粒子および前記支持体間に前記半導体または前記良導体を付与することを特徴とする、
光水分解反応用電極の製造方法。 As a photocatalyst constituting photocatalyst particles, there is provided a method for producing an electrode for photohydrolysis reaction in which at least one selected from the group consisting of oxynitride, nitride, oxysulfide, and sulfide is deposited on a support. And
Between the photocatalyst particles and between the photocatalyst particles and the support, the semiconductor or good conductor has TiN, TiO 2 , Ta 3 N 5 , TaON, ZnO, SnO 2 , ITO, Ag, Au, C, Cu, Cd, Co, Cr, Fe, Ga, Ge, Hg, Ir, In, Mn, Mo, Ni, Nb, Pb, Ru, Re, Rh, Sn, Sb, Ta, Ti, V, W, and any one of these alloys and mixtures,
The semiconductor or the good conductor is imparted between the photocatalyst particles and between the photocatalyst particles and the support by performing a heat treatment after coating the surface of the photocatalyst particles and the support with the precursor of the semiconductor or the good conductor. Features
A method for producing an electrode for photohydrolysis reaction.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2016035141A JP6270884B2 (en) | 2016-02-26 | 2016-02-26 | Method for producing electrode for photohydrolysis reaction |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2016035141A JP6270884B2 (en) | 2016-02-26 | 2016-02-26 | Method for producing electrode for photohydrolysis reaction |
Related Parent Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2014172639A Division JP2014223629A (en) | 2014-08-27 | 2014-08-27 | Electrode for photolytic water decomposition reaction using photocatalyst |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP2016144804A true JP2016144804A (en) | 2016-08-12 |
| JP6270884B2 JP6270884B2 (en) | 2018-01-31 |
Family
ID=56685138
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2016035141A Active JP6270884B2 (en) | 2016-02-26 | 2016-02-26 | Method for producing electrode for photohydrolysis reaction |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP6270884B2 (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2019078141A1 (en) * | 2017-10-17 | 2019-04-25 | 富士フイルム株式会社 | Water splitting device |
| JP2020153000A (en) * | 2019-03-22 | 2020-09-24 | 株式会社豊田中央研究所 | Electrochemical reaction device |
| CN112206802A (en) * | 2020-09-28 | 2021-01-12 | 苏州阿德旺斯新材料有限公司 | Preparation method of monatomic catalyst, prepared product and application |
| CN117205944A (en) * | 2023-03-16 | 2023-12-12 | 盐城工学院 | Novel oxysulfide photocatalyst and preparation method and application thereof |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH1128364A (en) * | 1997-07-11 | 1999-02-02 | Toshiba Corp | Photocatalyst composite body and water purification device |
| JP2005133174A (en) * | 2003-10-31 | 2005-05-26 | Toyota Motor Corp | Water decomposition type hydrogen generation cell |
| JP2005161203A (en) * | 2003-12-02 | 2005-06-23 | Japan Science & Technology Agency | Metal oxynitride electrode catalyst |
| WO2006010926A1 (en) * | 2004-07-26 | 2006-02-02 | Hydrogen Solar Ltd | Photoactive layer, photoactive electrode and process for preparation |
| JP2008155111A (en) * | 2006-12-22 | 2008-07-10 | Univ Of Tokyo | Acid resistant electrode catalyst |
-
2016
- 2016-02-26 JP JP2016035141A patent/JP6270884B2/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH1128364A (en) * | 1997-07-11 | 1999-02-02 | Toshiba Corp | Photocatalyst composite body and water purification device |
| JP2005133174A (en) * | 2003-10-31 | 2005-05-26 | Toyota Motor Corp | Water decomposition type hydrogen generation cell |
| JP2005161203A (en) * | 2003-12-02 | 2005-06-23 | Japan Science & Technology Agency | Metal oxynitride electrode catalyst |
| WO2006010926A1 (en) * | 2004-07-26 | 2006-02-02 | Hydrogen Solar Ltd | Photoactive layer, photoactive electrode and process for preparation |
| JP2008155111A (en) * | 2006-12-22 | 2008-07-10 | Univ Of Tokyo | Acid resistant electrode catalyst |
Non-Patent Citations (4)
| Title |
|---|
| RYU ABE ET AL.: "The Use of TiCl4 Treatment to Enhance the Photocurrent in a TaON Photoelectrode under Visible Light", CHEMISTRY LETTERS, vol. 34, no. 8, JPN6017015171, 2005, JP, pages 1162 - 1163, ISSN: 0003548305 * |
| 橋口弘ら: "ＩｒＯ２担持によるＧａＮ：ＺｎＯ電極の光電流の向上", 第９９回触媒討論会討論会Ａ予稿集, JPN6013059064, 28 March 2007 (2007-03-28), pages 2 - 64, ISSN: 0003694530 * |
| 西村直之他: "Ta3N5薄膜電極の光電気化学特性", 日本化学会講演予稿集, vol. 88, no. 1, JPN6017015173, 12 March 2008 (2008-03-12), JP, pages 439, ISSN: 0003548307 * |
| 阿部竜他: "オキシナイトライドTaONの薄膜化による高性能可視光応答性光電極の作成", 電気化学会大会講演要旨集, vol. 73, JPN6017015172, 1 April 2006 (2006-04-01), JP, pages 203, ISSN: 0003548306 * |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2019078141A1 (en) * | 2017-10-17 | 2019-04-25 | 富士フイルム株式会社 | Water splitting device |
| JPWO2019078141A1 (en) * | 2017-10-17 | 2020-11-05 | 富士フイルム株式会社 | Water decomposition equipment |
| JP2020153000A (en) * | 2019-03-22 | 2020-09-24 | 株式会社豊田中央研究所 | Electrochemical reaction device |
| CN112206802A (en) * | 2020-09-28 | 2021-01-12 | 苏州阿德旺斯新材料有限公司 | Preparation method of monatomic catalyst, prepared product and application |
| CN117205944A (en) * | 2023-03-16 | 2023-12-12 | 盐城工学院 | Novel oxysulfide photocatalyst and preparation method and application thereof |
| CN117205944B (en) * | 2023-03-16 | 2024-04-30 | 盐城工学院 | Oxysulfide photocatalyst and preparation method and application thereof |
Also Published As
| Publication number | Publication date |
|---|---|
| JP6270884B2 (en) | 2018-01-31 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP5641499B2 (en) | Photocatalytic photocatalytic electrode | |
| Nasir et al. | New insights into Se/BiVO4 heterostructure for photoelectrochemical water splitting: a combined experimental and DFT study | |
| Fu et al. | Identifying performance-limiting deep traps in Ta3N5 for solar water splitting | |
| Dubale et al. | Heterostructured Cu 2 O/CuO decorated with nickel as a highly efficient photocathode for photoelectrochemical water reduction | |
| Liu et al. | All inorganic semiconductor nanowire mesh for direct solar water splitting | |
| JP6082728B2 (en) | Electrode for water splitting reaction and method for producing the same | |
| Park et al. | Progress in bismuth vanadate photoanodes for use in solar water oxidation | |
| Yang et al. | In situ Sn-doped WO 3 films with enhanced photoelectrochemical performance for reducing CO 2 into formic acid | |
| Li et al. | Templating sol–gel hematite films with sacrificial copper oxide: enhancing photoanode performance with nanostructure and oxygen vacancies | |
| JP6270884B2 (en) | Method for producing electrode for photohydrolysis reaction | |
| Rosa et al. | Ternary Oxide CuWO4/BiVO4/FeCoO x Films for Photoelectrochemical Water Oxidation: Insights into the Electronic Structure and Interfacial Band Alignment | |
| JP5548923B2 (en) | Electrode for water splitting, method for producing electrode for water splitting, and water splitting method | |
| Xu et al. | Complex-mediated synthesis of tantalum oxyfluoride hierarchical nanostructures for highly efficient photocatalytic hydrogen evolution | |
| Ahn et al. | MoS x supported hematite with enhanced photoelectrochemical performance | |
| Lin et al. | Robust ZnO nanowire photoanodes with oxygen vacancies for efficient photoelectrochemical cathodic protection | |
| Song et al. | Nonequilibrium deposition in epitaxial BiVO4 thin film photoanodes for improving solar water oxidation performance | |
| Salehmin et al. | Recent advances on state-of-the-art copper (I/II) oxide as photoelectrode for solar green fuel generation: Challenges and mitigation strategies | |
| Kalanoor et al. | Multiple ion doping in BiVO4 as an effective strategy of enhancing photoelectrochemical water splitting: a review | |
| Hu et al. | A high-activity bimetallic OER cocatalyst for efficient photoelectrochemical water splitting of BiVO 4 | |
| Yang et al. | Boosted water oxidation activity and kinetics on BiVO4 photoanodes with multihigh-index crystal facets | |
| Son et al. | Structural and compositional investigations on the stability of cuprous oxide nanowire photocathodes for photoelectrochemical water splitting | |
| Shaddad et al. | Unprecedented solar water splitting of dendritic nanostructured Bi2O3 films by combined oxygen vacancy formation and Na2MoO4 doping | |
| Khan et al. | Sustained Water Oxidation with Surface-and Interface-Engineered WO3/BiVO4 Heterojunction Photoanodes | |
| Peng et al. | Boosting the electrochemical CO2 reduction performance by Cu2O/β-Bi2O3 bimetallic heterojunction with the assistance of light | |
| JP2014223629A (en) | Electrode for photolytic water decomposition reaction using photocatalyst |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A977 | Report on retrieval |
Free format text: JAPANESE INTERMEDIATE CODE: A971007 Effective date: 20161108 |
|
| A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20161115 |
|
| A521 | Request for written amendment filed |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20170111 |
|
| A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20170502 |
|
| A711 | Notification of change in applicant |
Free format text: JAPANESE INTERMEDIATE CODE: A712 Effective date: 20170525 |
|
| A601 | Written request for extension of time |
Free format text: JAPANESE INTERMEDIATE CODE: A601 Effective date: 20170629 |
|
| A521 | Request for written amendment filed |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20170901 |
|
| TRDD | Decision of grant or rejection written | ||
| A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 Effective date: 20171205 |
|
| A61 | First payment of annual fees (during grant procedure) |
Free format text: JAPANESE INTERMEDIATE CODE: A61 Effective date: 20171226 |
|
| R150 | Certificate of patent or registration of utility model |
Ref document number: 6270884 Country of ref document: JP Free format text: JAPANESE INTERMEDIATE CODE: R150 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |